Abstract: Using the ground-based observations at Lhasa and NamCo stations, the daily and seasonal variations of Aerosol Optical Depth (AOD) at Lhasa were investigated along with the preliminary validation of the quality and the adaptability of MODIS products. Results show that the AOD at Lhasa existed obvious fluctuation from 8 to 10 Am and 5 to 8 Pm while it’s quite stable from 11Am to 4Pm. The seasonal variation exhibited different distribution at above two stations. The AOD at Lhasa indicated one peak and the AOD at NamCo presented double peaks variation with the maximum value in spring. The maximum value of seasonal variation might be related to the dust weather in spring. The AOD at Lhasa was larger than that at NamCo station as a whole with smaller angstrom wavelength index, this phenomenon probably connected with urban human activity and the aerosol product derived from MODIS was not suitable in Lhasa.